The present invention relates to the field of needle stick prevention devices for syringes. After administering an injection, or after withdrawing fluid from a patient, a used syringe presents a safety hazard. Various infectious diseases, such as AIDS and hepatitis B, can be transmitted through the transfer of a small amount of blood from a needle stick. Needle stick prevention devices prevent inadvertent needle sticks from used syringes.
Often, the doctor or nurse does not dispose of the syringe immediately and the syringe lies with the needle unprotected. A passerby or even the person administering the injection can inadvertently contact the needle and receive a needle stick. Even after the syringe is disposed of the needle presents a possible hazard to people who handle the waste containers. If the syringe is disposed of in a conventional trash bag, the needle can pierce the bag and stick the person handling the bag.
A needle stick prevention device is disclosed in U.S. Pat. No. 4,850,994 to Zerbst. A protective cylinder 20 is used to cover the syringe after the injection (FIG. 12 of Zerbst). A back stop 21 engages a catch point 28 which is molded integral with the barrel to prevent the cylinder 20 from moving from the protection position.
A problem with Zerbst is that the cylinder is longer than necessary which adds cost to the device. The catch point 28 of Zerbst is molded in the barrel so that the cylinder 20 not only covers the needle, but part of the barrel as well.
A further problem with Zerbst is that the device cannot be used with a standard syringe. The syringe of Zerbst is specially manufactured with a barrel having the catch point 28 molded into the barrel of the syringe.